Page and Brin founded Google in 1998.[23] Google attracted a loyal following among the growing number of Internet users, who liked its simple design.[24] Off-page factors (such as PageRank and hyperlink analysis) were considered as well as on-page factors (such as keyword frequency, meta tags, headings, links and site structure) to enable Google to avoid the kind of manipulation seen in search engines that only considered on-page factors for their rankings. Although PageRank was more difficult to game, webmasters had already developed link building tools and schemes to influence the Inktomi search engine, and these methods proved similarly applicable to gaming PageRank. Many sites focused on exchanging, buying, and selling links, often on a massive scale. Some of these schemes, or link farms, involved the creation of thousands of sites for the sole purpose of link spamming.[25]
To prevent users from linking to one version of a URL and others linking to a different version (this could split the reputation of that content between the URLs), focus on using and referring to one URL in the structure and internal linking of your pages. If you do find that people are accessing the same content through multiple URLs, setting up a 301 redirect32 from non-preferred URLs to the dominant URL is a good solution for this. You may also use canonical URL or use the rel="canonical"33 link element if you cannot redirect.
Imagine that you've created the definitive Web site on a subject -- we'll use skydiving as an example. Your site is so new that it's not even listed on any SERPs yet, so your first step is to submit your site to search engines like Google and Yahoo. The Web pages on your skydiving site include useful information, exciting photographs and helpful links guiding visitors to other resources. Even with the best information about skydiving on the Web, your site may not crack the top page of results on major search engines. When people search for the term "skydiving," they could end up going to inferior Web sites because yours isn't in the top results.
Keywords. Keyword research is the first step to a successful SEO strategy. Those successful with SEO understand what people are searching for when discovering their business in a search engine. These are the keywords they use to drive targeted traffic to their products. Start brainstorming potential keywords, and see how the competition looks by using Google AdWords Keyword Tool. If you notice that some keywords are too competitive in your niche, go with long-tail keywords (between two and five words) which will be easier for you to rank. The longer the keyword, the less competition you will have for that phrase in the engines.

SEO techniques can be classified into two broad categories: techniques that search engine companies recommend as part of good design ("white hat"), and those techniques of which search engines do not approve ("black hat"). The search engines attempt to minimize the effect of the latter, among them spamdexing. Industry commentators have classified these methods, and the practitioners who employ them, as either white hat SEO, or black hat SEO.[50] White hats tend to produce results that last a long time, whereas black hats anticipate that their sites may eventually be banned either temporarily or permanently once the search engines discover what they are doing.[51]

You mentioned: "many times clients have already done this work. Ask them for copies of their market research reports when you start a project. It will save you a ton of time and effort!" We do this with most of our clients, like you said we have found that around 75% of the have some kind of Market research done, that saves you a lot of time and helps setting up the right SEO Strategy.
Make it as easy as possible for users to go from general content to the more specific content they want on your site. Add navigation pages when it makes sense and effectively work these into your internal link structure. Make sure all of the pages on your site are reachable through links, and that they don't require an internal "search" functionality to be found. Link to related pages, where appropriate, to allow users to discover similar content.
Social media. The algorithms have truly changed since social media first emerged. Many content websites are community-oriented -- Digg began allowing users to vote which stories make the front page, and YouTube factors views and user ratings into their front page rankings. Therefore, e-commerce stores must establish a strong social media presence on sites like Facebook , Pinterest, Twitter, etc. These social media sites send search engines signals of influence and authority.
We expect advertisements to be visible. However, you should not let the advertisements distract users or prevent them from consuming the site content. For example, advertisements, supplement contents, or interstitial pages (pages displayed before or after the content you are expecting) that make it difficult to use the website. Learn more about this topic.38
By 2004, search engines had incorporated a wide range of undisclosed factors in their ranking algorithms to reduce the impact of link manipulation. In June 2007, The New York Times' Saul Hansell stated Google ranks sites using more than 200 different signals.[26] The leading search engines, Google, Bing, and Yahoo, do not disclose the algorithms they use to rank pages. Some SEO practitioners have studied different approaches to search engine optimization, and have shared their personal opinions.[27] Patents related to search engines can provide information to better understand search engines.[28] In 2005, Google began personalizing search results for each user. Depending on their history of previous searches, Google crafted results for logged in users.[29]
While short-tail keywords are often searched more frequently, it is more difficult to rank for them on search engines. Targeting long-tail keywords, on the other hand, gives you a better chance of ranking higher (even on the first page) for queries specific to your products and services—and higher ranking means more traffic. Plus, as search engines and voice-to-text capabilities advance, people are using more specific phrases to search online. There are many free tools available to help you find keywords to target, such as Answer the Public.
#6 Go on podcasts! In 13 years of SEO and digital marketing, I’ve never had as much bang for the buck. You go on for 20 minutes, get access to a new audience and great natural links on high dwell time sites (hosts do all the work!). Thanks for including this tip Brian, I still don’t think the SEO community has caught on to the benefits of podcast guesting campaigns for SEO and more…it’s changed my business for sure.
If you havent see it already, check out the links in shor's comment below - there are some great resources in there. In some cases you can also consider surveying your current audience or customers through email, on-site surveys or SurveyMonkey. Be sure to ask for some profiling information that you can use for determining specific persona needs like age, sex, location, etc. (Probably best not to make it sound like a creepy text chat like I just did though...) :)
What are the pain points? What things drive the members of this organization to drink? From the customer support to the higher-ups, there are things that knock the company down. How do they get back up? Why are the pains they're looking to work around? It may not be realistic to interview the whole company, but ideally you can get a representative to answer these.
Having an industry influencer publish a blog post on your site or turning an interview with them into a blog post can help to drive traffic both through organic search but also via that influencer promoting the content to their audience (see the backlinks section above). This can also help to add more variety to your content and show your visitors that you are active in your field.
Add relevant links back to your site. Throughout your answer, sprinkle a few relevant links back to your website. The more relevant they are to the question, the more clicks and traffic they will generate. You can also finish your answers with a link to your lead magnet, concluding with something like this: “Want to know more about how to start a business? Check out my free checklist with 10 steps for starting your first business!” and a link to the lead magnet (in this example, the checklist).